Change Travis-CI to execute on newer Ubuntu xenial version. (#209)

Author: tobiasake

.travis.yml

@@ -1,16 +1,15 @@
 sudo: required
 
+dist: xenial
+
 language: java
 
 services:
   - docker
 
-jdk:
-  - oraclejdk8
-
 env:
   - EI_BACKEND_PORT=8099
-
+  - JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-amd64
 
 # Using default 'test' stage for our tests, and only running deploy stage
 # (after merge) on master branch
@@ -21,6 +20,12 @@ stages:
 
 
 before_install:
+  - sudo apt-get update
+  - sudo apt-get install -y openjdk-8-jdk
+  - export PATH=$(echo "$PATH" | sed -e 's/:\/usr\/local\/lib\/jvm\/openjdk11\/bin//')
+  - export PATH=/usr/lib/jvm/java-8-openjdk-amd64/bin:$PATH
+  - export JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-amd64
+  - java -version
   - source src/main/docker/env.bash
   - docker-compose -f src/main/docker/docker-compose.yml up -d eiffel-er mongodb rabbitmq jenkins mail-server
 
@@ -54,6 +59,13 @@ jobs:
       before_install: skip
       install: skip
       script:
+        - sudo apt-get update
+        - sudo apt-get install -y openjdk-8-jdk
+        - export PATH=$(echo "$PATH" | sed -e 's/:\/usr\/local\/lib\/jvm\/openjdk11\/bin//')
+        - export PATH=/usr/lib/jvm/java-8-openjdk-amd64/bin:$PATH 
+        - echo $PATH
+        - export JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-amd64
+        - java -version
         - mvn test -B
       after_script: skip
     - stage: test